Dissolvable personal care films are known comprising a water-soluble polymeric structurant and a surfactant or other active ingredient. However, in order to achieve the requisite rapid dissolution rates needed for consumer convenience, these films are generally on the order of less than 100 microns thickness (typically 50 microns) and, thereby, are generally of too low a basis weight (typically 50-100 grams of solid per square meter) to enable feasible consumer application of a sufficient dosage of active ingredients for entire body or whole head hair application and performance, i.e., beyond lower dosage applications such as hand cleansing and/or the facial applications.
Dissolvable porous solid personal care products have been taught comprising natural starch and surfactants (See US 2004/0048759). However, these porous solids were produced by an anhydrous extrusion process and employing volatile blowing agents to produce the cellular structure via high pressure drop induced expansion of the solid. The anhydrous process limits the components available to anhydrous materials such as solid-sourced surfactants which are unacceptably harsh to skin, hair and fabric surfaces and are known for “skin” formation due to the partial collapse of structure after the abrupt high pressure drop at the exit of the extruder die also termed “shrinkage”. Such skins are unacceptable as these would serve as a barrier for water ingress to the interior and adversely affect dissolution rates.
Freeze-dried open-celled porous solids for personal care have been taught (See U.S. Pat. No. 6,106,849 and US 2007/0225388). However, such resulting freeze-dried porous solids are rigid, brittle and fragile and without plasticization of the polymer such that it remains in its glassy state to avoid collapse of the structure during the process (See U.S. Pat. No. 5,457,895 Kearney P. et. al., issued 1995). Also, freeze-drying is a relatively high energy and costly process.
Therefore a need exists for a process that results in a desired flexible, dissolvable porous solid structure which can be easily and quickly manufactured that gives the desired properties of flexibility, dissolution, surfactant dosing levels and lather by consumers utilizing such articles.